scholarly journals Analysis of Rainfall Variability and Trends Over Nzoia River Basin, Kenya

2021 ◽  
pp. 26-52
Author(s):  
Ernest Othieno Odwori ◽  
Jacob Wanambacha Wakhungu
Keyword(s):  
Economic Development ◽  
Regression Analysis ◽  
Water Resources ◽  
Linear Regression ◽  
River Basin ◽  
Water Resources Management ◽  
Rainfall Variability ◽  
Linear Regression Analysis ◽  
Annual Rainfall ◽  
Resources Management

Nzoia river is mainly rain fed and the basin is one of the regions that is highly vulnerable to climate change in Kenya. Understanding rainfall variability and trends is important for better water resources management and economic development in the basin. The aim of this study is to assess variability and trends in rainfall at 13 sites within Nzoia River Basin over the period, 1970 to 2001, using the parametric test of Linear regression analysis and the non-parametric Mann–Kendall statistical test. Data for this study was obtained from the Kenya Meteorological Department (KMD). The basin experiences four rainfall seasons in a year as a result of the Inter-Tropical Convergence Zone (ITCZ). There are two rainy seasons and two dry seasons. Annual rainfall through Linear regression analysis shows 6 stations, Kaimosi Tea Estate Ltd, Kakamega Meteorological Station, Bungoma Water Supply, Nzoia Forest Station, Malava Forest Station and Webuye Agricultural Office with declining rainfalls. The remaining 7 stations, Leissa Farm Kitale, Turbo Forest Nursery, Chorlim ADC Farm, Kaptagat Forest Station, Kimilili Agricultural Department, Bunyala Irrigation Scheme and Kadenge Yala Swamp showed increasing rainfalls. The majority of stations with increasing annual rainfall are in the upper catchment whereas those with decreasing rainfall are in the middle and lower catchment. Only 3 out of the 13 stations showed statistically significant trends in rainfall with two in the upper catchment and one in the middle; the remaining 10 stations had statistically insignificant trends. These observed changes in rainfall, although most time series are not convincing as they show predominantly no significance, along with the reported climatic warming in most parts of the basin may have future implications on human health, water resources management, various plant and animal species bio-diversity and the overall economic development of the basin.

scholarly journals Vulnerability of Calabar Rainfall to Climatic Variability Events: A Critical Factor in Integrated Water Resources Management in the Tropical Coastal Location in Southeastern Nigeria

2021 ◽  
Vol 16 (1) ◽  
pp. 115-122
Author(s):  
Solomon O. Amadi ◽  
Mfongang E. Agbor ◽  
Sunday O. Udo
Keyword(s):  
Water Resources ◽  
Water Resources Management ◽  
Rainfall Variability ◽  
Climatic Variability ◽  
Standardized Precipitation Index ◽  
Annual Rainfall ◽  
Least Squares Regression ◽  
Southeastern Nigeria ◽  
Resources Management ◽  
Dry Spell

In this study, Calabar annual total rainfall was analysed for trend and climatic variability events with focus on drought occurrence. Monthly rainfall data from in situ measurements over a 41 year period (1972-2012) were used for the study. Standard tests were used to evaluate the trends and variability in annual rainfall. Rainfall variability was estimated as standardized rainfall departures and used to identify and delimitate the dry and wet spell sequences of Calabar rainfall. The rainfall series were analysed for Standardized Precipitation Index (SPI) using SPSS Version 17 software. The least squares regression plot was executed using Excel 2010 to depict the trend, variability and regression parameters. The average annual rainfall for Calabar is 2984.64 mm with standard deviation of 394.9 mm. 36.59% of the period showed positive SPI while 63.41 % of the period indicated negative SPI values. Wet spell dominated the later part of the period but sandwiched with dry spells whereas dry spell were dominant from 1972 to 1994. The area experienced a non-significant upward trend of 15.21 mm per year over the interval. The SPI values indicate that Calabar experienced distinct inter-annual rainfall cycles that represent mild to extreme droughts and wet spells which are a demonstration of consequential annual rainfall variability. The results underscore the need for effective monitoring of Calabar rainfall for prompt warnings and responses that would guarantee effective risk reduction and management in the run-in to the occurrence of the extreme events. The paper further highlights the need for data-driven approach to policy making in water resources management. This would provide a fascinating insight into the improvement in long-term water resources management in the city and its suburbs.

scholarly journals Analysis of Vulnerability of Calabar Rainfall to Climatic Variability Events: A Critical Factor in Integrated Water Resources Management in the Tropical Coastal Location in Southeastern Nigeria

2021 ◽  
Vol 8 (1) ◽  
pp. 53-60
Author(s):  
Solomon O. Amadi ◽  
Mfongang E. Agbor ◽  
Sunday O. Udo
Keyword(s):  
Water Resources ◽  
Water Resources Management ◽  
Rainfall Variability ◽  
Climatic Variability ◽  
Standardized Precipitation Index ◽  
Annual Rainfall ◽  
Least Squares Regression ◽  
Southeastern Nigeria ◽  
Resources Management ◽  
Dry Spell

In this study, Calabar annual total rainfall was analysed for trend and climatic variability events with focus on drought occurrence. Monthly rainfall data from in situ measurements over a 41-year period (1972-2012) were used for the study. Standard tests were used to evaluate the trends and variability in annual rainfall. Rainfall variability was estimated as standardized rainfall departures and used to identify and delimitate the dry and wet spell sequences of Calabar rainfall. The rainfall series were analysed for Standardized Precipitation Index (SPI) using SPSS Version 17 software. The least squares regression plot was executed using Excel 2010 to depict the trend, variability and regression parameters. The average annual rainfall for Calabar is 2984.64 mm with standard deviation of 394.9 mm. 36.59% of the period showed positive SPI while 63.41% of the period indicated negative SPI values. Wet spell dominated the later part of the period but sandwiched with dry spells whereas dry spell was dominant from 1972 to 1994. The area experienced a non-significant upward trend of 15.21 mm per year over the interval. The SPI values indicate that Calabar experienced distinct inter-annual rainfall cycles that represent mild to extreme droughts and wet spells which are a demonstration of consequential annual rainfall variability. The results underscore the need for effective monitoring of Calabar rainfall for prompt warnings and responses that would guarantee effective risk reduction and management in the run-in to the occurrence of the extreme events. The paper further highlights the need for data-driven approach to policy making in water resources management. This would provide a fascinating insight into the improvement in long-term water resources management in the city and its suburbs.

scholarly journals An ice core derived 1013-year catchment-scale annual rainfall reconstruction in subtropical eastern Australia

2016 ◽  
Vol 20 (5) ◽  
pp. 1703-1717 ◽  
Author(s):  
Carly R. Tozer ◽  
Tessa R. Vance ◽  
Jason L. Roberts ◽  
Anthony S. Kiem ◽  
Mark A. J. Curran ◽  
...  
Keyword(s):  
Water Resources ◽  
Water Resources Management ◽  
Rainfall Variability ◽  
Full Range ◽  
Ice Cores ◽  
Annual Rainfall ◽  
Catchment Scale ◽  
Resources Management ◽  
Eastern Australia ◽  
Hydroclimatic Variability

Abstract. Paleoclimate research indicates that the Australian instrumental climate record (∼ 100 years) does not cover the full range of hydroclimatic variability that is possible. To better understand the implications of this on catchment-scale water resources management, a 1013-year (1000–2012 common era (CE)) annual rainfall reconstruction was produced for the Williams River catchment in coastal eastern Australia. No high-resolution paleoclimate proxies are located in the region and so a teleconnection between summer sea salt deposition recorded in ice cores from East Antarctica and rainfall variability in eastern Australia was exploited to reconstruct the catchment-scale rainfall record. The reconstruction shows that significantly longer and more frequent wet and dry periods were experienced in the preinstrumental compared to the instrumental period. This suggests that existing drought and flood risk assessments underestimate the true risks due to the reliance on data and statistics obtained from only the instrumental record. This raises questions about the robustness of existing water security and flood protection measures and has serious implications for water resources management, infrastructure design and catchment planning. The method used in this proof of concept study is transferable and enables similar insights into the true risk of flood/drought to be gained for other paleoclimate proxy poor regions for which suitable remote teleconnected proxies exist. This will lead to improved understanding and ability to deal with the impacts of multi-decadal to centennial hydroclimatic variability.

Integrated water resources management in the Ruhr River Basin, Germany

2003 ◽  
Vol 47 (7-8) ◽  
pp. 81-86 ◽  
Author(s):  
H. Bode ◽  
P. Evers ◽  
D.R. Albrecht
Keyword(s):  
Water Resources ◽  
Water Supply ◽  
River Basin ◽  
Water Resources Management ◽  
Ecological Status ◽  
Integrated Water Resources Management ◽  
Rhine River ◽  
Wastewater Disposal ◽  
Resources Management ◽  
The People

The Ruhr, with an average flow of 80.5 m3/s at its mouth, is a comparatively small tributary to the Rhine River that has to perform an important task: to secure the water supply of more than 5 million people and of the industry in the densely populated region north of the river. The complex water management system and network applied by the Ruhrverband in the natural Ruhr River Basin has been developed step by step, over decades since 1913. And from the beginning, its major goal has been to achieve optimal conditions for the people living in the region. For this purpose, a functional water supply and wastewater disposal infrastructure has been built up. The development of these structures required and still requires multi-dimensional planning and performance. Since the river serves as receiving water and at the same time as a source of drinking water, the above-standard efforts of Ruhrverband for cleaner water also help to conserve nature and wildlife. Ruhrverband has summed up its environmental awareness in the slogan: “For the people and for the environment”. This basic water philosophy, successfully applied to the Ruhr for more than 80 years, will be continued in accordance with the new European Water Framework Directive, enacted in 2000, which demands integrated water resources management in natural river basins, by including the good ecological status of surface waterbodies as an additional goal.

Sign in / Sign up

Export Citation Format

Share Document